Embodiments presented herein relate generally to a torsional sensor including a high-pressure sealing mechanism used for measurement of at least one parameter of a high-pressure fluid by the propagation of torsional wave energy along the torsional sensor located at least partially in contact with the high-pressure fluid.
In industrial process control, it is often required to determine at least one parameter attributed to fluids along flow paths, for example in pipes. The parameters may include density of the fluid, fluid velocity, fluid level, temperature, fluid phase, or the like. There are a number of known sensors, which are used for detection of parameters associated with the fluids.
One such sensor used for detection of parameters associated with the fluids is a torsional sensor. In such a device, the torsional sensor is at least partially inserted into the fluid whose property needs to be measured. Wave energy is guided along the sensor held at least partially in contact with the fluid. The parameter of the fluid surrounding the torsional sensor influences the torsional wave characteristics, specifically the time of flight of the wave mode. In other words, the interaction of the guided wave energy along the sensor with the fluid results in a lower velocity of propagation of the guided wave energy along the sensor, so that the change in flight time of the wave, as compared to a reference time with the sensor in air or vacuum, provides an indication of a parameter of the fluid in contact with the sensor. In particular circumstances, where at least one of the fluid composition, container geometry and sensor characteristics are known, a measurement of flight time of the wave energy guided along the sensor may provide an indication of a parameter of the fluid. However, known torsional sensor designs are not suitable for operation in high-pressure environments, such as inside a high-pressure liquid pipeline at isostatic pressures of up to approximately 1380 bar. Previous attempts to design a high-pressure torsional sensor included forming a glass to metal seal around the torsional rod with the piezoelectric element on a low-pressures side of a mounting flange. This resulted in significant acoustic energy reflection from the glass to metal seal and reduced signal to noise ratio.
As a result, there is a continued need for an improved high-pressure torsional sensor and more specifically, a high-pressure torsional sensor that includes a high-pressure sealing mechanism to address the aforementioned and other shortcomings